grotto

README

Grotto

A permissive, user-friendly gRPC client with a native desktop GUI.

Features

• Reflection-based discovery — Automatically discovers services and methods via gRPC Server Reflection, with permissive handling of malformed server descriptors
• Dual interaction modes:
  • Form mode — Auto-generated forms with validation, nested message support, maps, repeated fields, and oneofs
  • Text mode — Direct JSON editing with bidirectional sync to form mode
• Smart optional fields — Proto3 optional fields and single-member oneofs render as toggle checkboxes instead of dropdowns, with proper field presence semantics
• Syntax-colored responses — JSON responses with color-coded keys, strings, numbers, and booleans, plus a select mode for text copying
• Copy to clipboard — One-click copy button for response data (unary and streaming)
• Streaming support — Unary, server streaming, client streaming, and bidirectional streaming RPCs
• Well-known types — Native form widgets for Timestamp (RFC3339), Duration, and FieldMask fields
• Metadata — Send and inspect gRPC request/response metadata headers
• TLS support — Secure connections with configurable TLS, mTLS, and skip-verify options
• Workspaces — Save and load connections, selected methods, and request data
• Request history — Click to load previous requests into the UI, or replay them with a single click
• Keyboard shortcuts — See SHORTCUTS.md for the full list

Install

Homebrew (macOS)

brew install shhac/tap/grotto

Build from source

Requires Go 1.25+ and Fyne system dependencies.

go build -o grotto ./cmd/grotto
./grotto

Development

Test Servers

The project includes several test gRPC servers for development and testing. See testdata/README.md for details.

License

MIT